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The NaCl Debacle Part 2: We don’t need no stinkin’ science!

Sodium-Slashing Superheroes Low-Sodium Larry and his bodacious side-kick Linda “The Less Salt the Better” Van Horn team up to protect Americans from the evils lurking in a teaspoon of salt!(Drawings courtesy of Butcher Billy)

Larry and Linda KNOW that salt is BAD. Science? They don’t need no stinkin’ science.

Because the one thing everyone seems to be able to agree on is that the science on salt does indeed stink. The IOM report has had to use many of the same methodologically-flawed studies available to the 2010 Dietary Guidelines Advisory Committee, full of the same confounding, measurement error, reverse causation and lame-ass dietary assessment that we know and love about all nutrition epidemiology studies. But the 2010 Dietary Guidelines Advisory Committee didn’t actually bother to look at these studies.

Use this suggestion to establish some arbitrary clinical cut offs for when this marker is “good” and “bad.” (Note to public health advocacy organizations: Be sure to frequently move those goalposts in whichever direction requires more pharmaceuticals to be purchased from the companies that sponsor you.)

Find some dietary factor that can easily and profitably be removed from our food supply, but whose intake is difficult to track (like saturated fat, sodium, calories).

Implicate the chosen food factor in the regulation of the arbitrary marker, the details of which we don’t quite understand. (How? Use observational data—see methodological flaws above—but hunches and wild guesses will also work.)

Create policy that insists that the entire population—including people who, by the way, are not (at least at this point) fat, sick or dead—attempt to prevent this chronic disease by avoiding this particular dietary factor. (Note to public health advocacy organizations: Be sure to offer food manufacturers the opportunity to have the food products from which they have removed the offensive component labeled with a special logo from your organization—for a “small administrative fee,” of course.)

Commence collecting weak, inconclusive, and inconsistent data to prove that yes indeedy this dietary factor we can’t accurately measure does in fact have some relationship to this arbitrary clinical marker, whose regulation and health implications we don’t fully understand.

Finally—here’s the kicker—measure the success of your intervention by whether or not people are willing to eat expensive, tasteless, chemical-filled food devoid of the chosen food factor in order to attempt to regulate the arbitrary clinical marker.

Whatever you do, DO NOT EVER measure the success of your intervention by looking at whether or not attempts to follow your intervention has made people fat, sick, or dead in the process.

Ooops. I think I just described the entire history of nutrition epidemiology of chronic disease.

Blood pressure is easy to measure, but we don’t always know what causes it to go up (or down). There is no real physiological difference between having a blood pressure reading of 120/80, which will get you a diagnosis of “pre-hypertension” and a fistful of prescriptions, and a reading of 119/79, which won’t. Blood pressure is not considered to be a “distinct underlying cause of death,” which means that, technically, no one ever dies of blood pressure (high or low). We certainly don’t know how to disentangle the effects of lowering dietary sodium on blood pressure from other effects (like weight loss) that may be related to dietary changes that are a part of an attempt to lower sodium (and we have an embarrassingly hard time collecting accurate dietary intake information from Food Fantasy Questionnaires anyway). We also know that individual response to sodium varies widely.

So doesn’t it make perfect sense that the folks at the USDA/HHS should ignore science that investigates the relationship between sodium intake and whether or not a person stayed out of the hospital, had a heart attack, or up and died? Well, it doesn’t to me, but nevertheless the USDA/HHS has remained obsessively fixated on one thing and one thing only, what effects reducing sodium has on blood pressure, and they pay not one whit of attention to what effects reducing sodium has on, say, aliveness.

So let’s just get this out there and agree to agree: reducing sodium in most cases will reduce blood pressure. But then, just to be clear, so will dismemberment, dysentery, and death. We can’t just assume that lowering sodium will only affect blood pressure or will only positively affect health (I mean, we can’t unless we are Larry or Linda). Recent research, which prompted the IOM review, indicates that reducing sodium will also increase triglyceride levels, insulin resistance, and sympathetic nervous system activity. For the record, clinicians generally don’t consider these to be good things.

This may sound radical but in their review of the evidence, the IOM committee decided to do a few things differently.

First, they gave more weight to studies that determined sodium intake levels through multiple high-quality 24-hour urine collections. Remember, this is Low-Sodium Larry’s favorite way of estimating intake.

Also, they did not approach the data with a predetermined “healthy” range already established in their brains. Because of the extreme variability in intake levels among population groups, they decided to—this is crazy, I know—let the outcomes speak for themselves.

Finally, and most importantly, in the new IOM report, the authors, unlike Larry and Linda, focused on—hold on to your hats, folks!—actual health outcomes, something the Dietary Guidelines Have. Never. Done. Ever.

In other words, there is no science to indicate that we all need to be consuming less than ¾ of a teaspoon of salt a day. Furthermore, while there may be some subpopulations that may benefit from sodium reduction, reducing sodium intake to 1500 mg/day may increase risk of adverse health outcomes for people with congestive heart failure, diabetes, chronic kidney disease, or heart disease. (If you’d like to wallow in some of the studies reviewed by the IOM, I’ve provided the Reader’s Digest Condensed Version at the bottom of the page.)

No, folks that giant smacking sound you hear is not my head on my keyboard. That was the sound of science crashing into a giant wall of Consistent Public Health Message. Apparently, those public health advocates at the AHA seem to think that changing public health messages—even when they are wrong—confuses widdle ol’ Americans. The AHA—and the USDA/HHS team—doesn’t want us to have to worry our pretty little heads about all that crazy scientifical stuff with big scary words and no funny pictures or halftime shows.

Frankly, I appreciate that. I hate to have my pretty little head worried. But there’s one other problem with this particular Consistent Public Health Message. Not only is there no science to back it up; not only is it likely to be downright detrimental to the health of certain groups of people; not only is it likely to introduce an arsenal of synthetic chemical salt-replacements that will be consumed at unprecedented levels without testing for negative interactions or toxicities (remember how well that worked out when we replaced saturated fat with partially-hydrogenated vegetable oils?)—it is, apparently, incompatible with eating food.

While these researchers suggested that a feasibility study (this is a scientifical term for “reality check”) should precede the issuing of dietary guidelines to the public, I have a different suggestion.

How about we just stop with the whole 30-year-long dietary experiment to prevent chronic disease by telling Americans what not to eat? I hate to be the one to point this out, but it doesn’t seem to be working out all that well. It’s hard to keep assuming that the AHA and the USDA/HHS mean well when, if you look at it for what it is, they are willing to continue to jeopardize the health of Americans just so they don’t have to admit that they might have been wrong about a few things. I suppose if a Consistent Public Health Message means anything, it means never having to say you’re sorry for 30 years-worth of lousy dietary advice.

Weeeell, I got some bad news for you, Marion. Believe it. They have been delusional. They are making this up. And no, apparently there isno clinical or rational basis for the unanimity of these decisions.

But, thanks to the IOM report, perhaps we can no longer consider these decisions to be unanimous.

Praise the lard and pass the salt.

Read ’em and weep: The Reader’s Digest Condensed Version of the science from the IOM report. Studies marked with an asterix (*) are studies that were available to the 2010 Dietary Guidelines Advisory Committee.

Studies that looked at Cardiovascular Disease, Stroke, and Mortality

*Cohen et al. (2006)

When intakes of sodium less than 2300 mg per day were compared to intakes greater than 2300 mg per day, the “lower sodium intake was statistically significantly associated with increased risk of all-cause mortality.”

*Cohen et al. (2008)

When a fully-adjusted (for confounders) model was used, “there was a statistically significant higher risk of CVD mortality with the lowest vs. the highest quartile of sodium intake.”

Gardener et al. (2012)

Risk of stroke was positively related to sodium intake when comparing the highest levels of intake to the lowest levels of intake. There was no statistically significant increase in risk for those consuming between 1500 and 4000 mg of sodium per day.

*Larsson et al. (2008)

“The analyses found no significant association between dietary sodium intake and risk of any stroke subtype.”

*Nagata et al. (2004)

“Among men, a 2.3-fold increased risk of stroke mortality was associated with the highest tertile of sodium intake.” That sounds bad, but the average sodium intake in the high-risk group was 6613 mg per day. The lowest risk group had an average intake of 4070 mg per day. “Thus, the average sodium intake in the US would be within the lowest tertile of this study.”

Stolarz-Skrzypek at al. (2011)

“Overall, the authors found that lower sodium intake was associated with higher CVD mortality.”

Takachi et al. (2010)

The authors found “a significant positive association between sodium consumption at the highest compared to the lowest quintile and risk of stroke.” As with the Nagata (2004) study, this sounds bad, but the average sodium intake in the high-risk group was 6844 mg per day. The lowest risk group had an average intake of 3084 mg per day. “Thus, the average sodium intake in the US would be close to the lowest quintile of this study.”

*Umesawa et al. (2008)

“The authors found an association between greater dietary sodium intake and greater mortality from total stroke, ischemic stroke, and total CVD.” However, as with the Nagata and the Takchi studies (above), lower quintiles—in this case, quintiles one and two—would be comparable to average US intake.

Yang et al. (2011)

Higher usual sodium intake was found to be associated with all-cause mortality, but not cardiovascular disease mortality or ischemic heart disease mortality. “However, the finding that correction for regression dilution increased the effect on all-cause mortality, but not on CVD mortality, is inconsistent with the theoretical causal pathway.” In other words, high sodium intake might be bad for health, but not because it raises blood pressure and leads to heart disease.

Studies in Populations 51 Years of Age or Older

*Geleijnse et al. (2007)

“This study found no significant difference between urinary sodium level and risk of CVD mortality or all-cause mortality.” Relative risk was lowest in the medium intake group, with an average estimated intake of 2, 415 mg/day.

Other

“Five of the nine reported studies in the general population listed above also analyzed the data on health outcomes by age and found no interaction (Cohen et al., 2006, 2008; Cook et al., 2007; Gardener et al., 2012; Yang et al., 2011).”

Studies in Populations with Chronic Kidney Disease

Dong et al. (2010)

“The authors found that the lowest sodium intake was associated with increased mortality risk.”

Heerspink et al. (2012)

“Results from this study suggest that ARBs were more effective at decreasing CKD progression and CVD when sodium intake was in the lowest tertile” which had an estimated average sodium intake of about 2783 mg/day.

Studies on Populations with Cardiovascular Disease

Costa et al. (2012)

“Dietary sodium intake was estimated from a 62-itemvalidated FFQ. . . . Significant correlations were found between sodium intake and percentage of fat and calories in daily intake. . . . Overall, for the first 30 days and up to 4 years afterward, total mortality was significantly associated with high sodium intake.”

Kono et al. (2011)

“Cumulative risk analysis found that a salt intake of greater than the median of 4,000 mg of sodium) was associated with higher stroke recurrence rate. Univariate analysis of lifestyle management also found that poor lifestyle, defined by both high salt intake and low physical activity, was significantly associated with stroke recurrence.

O’Donnell et al. (2011)

“For the composite outcome, multivariate analysis found a U-shaped relationship between 24-hour urine sodium and the composite outcome of CVD death, MI, stroke, and hospitalization for CHF.” In other words, both higher (>7,000 mg per day estimated intake) and lower (<2,990 mg per day estimated intake) intakes of sodium were associated with increased risk of heart disease and mortality.

Studies on Populations with Prehypertension

*Cook et al. (2007)

In a randomized trial comparing a low sodium intervention with usual intake, lower sodium intake did not significantly decrease risk of mortality or heart disease events.

*Cook et al. (2009)

No significant increase in risk of adverse cardiovascular outcomes was associated with increased sodium excretions levels.

“Adjusted multivariate regression analysis found urinary sodium excretion was associated with incident CVD, with increased risk at both the highest [> 4,401 mg/day] and lowest [<2,346 mg/day] urine sodium excretion levels. When analyzed as independent outcomes, no significant associations were found between urinary sodium excretion and new CVD or stroke after adjustment for other risk factors.”

Other

“Two other studies discussed in this chapter analyzed the data on health outcomes by diabetes prevalence and found no interaction (Cohen et al., 2006; O’Donnell et al., 2011).”

“Results for event-free survival at a urinary sodium of ≥3,000 mg per day varied by the severity of patient symptoms.” In people with less severe symptoms, sodium intake greater than 3,000 mg per day was correlated with a lower disease incidence compared to those with a sodium intake less than 3,000 mg per day. Conversely, people with more severe symptoms who had a sodium intake greater than 3,000 mg per day had a higher disease incidence than those with sodium intakes less than 3,000 mg per day.

Parrinello et al. (2009)

“During the 12 months of follow-up, participants receiving the restricted sodium diet [1840 mg/day] had a greater number of hospital readmissions and higher mortality compared to those on the modestly restricted diet [2760 mg/day].”

*Paterna et al. (2008)

The lower sodium intake group [1840 mg/day] experienced a significantly higher number of hospital readmissions compared to the normal sodium intake group [2760 mg/day].

*Paterna et al. (2009)

A significant association was found between the low sodium intake [1,840 mg per day]) and hospital readmissions. The group with normal sodium diet [2760 mg/day] also had fewer deaths compared to all groups receiving a low-sodium diet combined.

How in the world did we get the IOM to do an unbiased review of Salt? and to do it the right way?

Can we get the IOM to do a similarly unbiased review of Saturated Fat, and Cholesterol?

Why did the CDC commission the IOM to look at salt and sodium again? when the science was already supposedly settled? Certainly the USDA Dietary Guidelines make it sound like settled science, so why did the CDC feel the need to look at the science again?

Those are great questions, and I can only guess at the answers. I think the CDC tends to be the Dragnet of government health-related groups–all they want are the facts–and they see facts being twisted to fit a particular agenda and their integrity as number-crunchers being called into question in the process.

Nowhere has this been more clear than in the recent dust-up about whether obesity reduces lifespan. CDC’s numero uno geek (and I say this with nothing but admiration and respect), Katherine Flegal, did quite a comprehensive evaluation of weight and mortality and found that, until you get to extreme levels of obesity, weight has little or no impact on mortality. Walter Willett and the Harvard gang were so incensed by this report (Willett called it “a pile of rubbish”), they convened a symposium to pick it apart. Why? Because it contradicts their beloved (and weakly supported) Public Health Message that everyone should be as lean as possible. (There will be a blog post on that before too long I hope.)

I get the impression that the 98-pound weakling science nerds at the CDC are tired of having sand kicked in their faces. I first noticed this with this report in 2010. It is “just the facts” but it calls very clearly for “further investigation” into the trend that shows that during the time that obesity has leveled off 1) total caloric intake has also plateaued 2) carbohydrate intake has decreased somewhat 2) protein intake has increased slightly and 3) fat and saturated fat intake has increased in some subpopulations. The CDC’s message seems to be: “Hmmmm. Hello Harvard? Something to think about.”

About the Willett-Flegal dust-up, I saw that! and was amazed that the news made it into Forbes magazine,

In an extraordinary editorial and feature article, Nature, one of the world’s pre-eminent scientific journals, has effectively admonished the chair of the Harvard School of Public Health’s nutrition department, Walter Willett, for promoting over-simplification of scientific results in the name of public health and engaging in unseemly behavior towards those who venture conclusions that differ to his.

This is so unfair. How can I like you so much and hate you at the same time, Adele? I like you because, clearly, you are an AWESOME writer and have a perspective that is full of wry humor, sarcasm, and scientific facts (or lack thereof!). I love how you challenge the established notions on just about all nutritional “wisdom” of the past half-century, and have taken the time to back it all up with what I can only imagine are hours of painstaking research and journal reading.

And I hate you for the same reasons. You are doing a better job of this than I could ever, ever hope to, and with a master’s in nutrition and a B.A. in creative writing, I’d like to think I could be pretty good at it if I wasn’t still working a full-time job in a completely unrelated industry and lack the time to devote to it. (For now.)

I would go line-by-line and high-five you for all the true zingers in this post, but that would pretty much be *every line*, so I’ll save myself the trouble. (The whole thing is fantastic, but I especially loved your 10-point list of how guidelines are created.)

The thing about sodium reduction maybe possibly leading to lower blood pressure reminds me of the statin issue — how even if they do lower cholesterol, we’re focused on one marker, rather than, as you said, “aliveness.” Maybe people will feel better when their nice, low numbers are carved on their headstone after they die prematurely from some *other* cause. 😉 (Yes, Sam died from liver failure, but we’re so relieved his total cholesterol was only 160 at time of death!”)

(And one final note, because I can’t resist: I guess when they no human alive should be excluded from the recommendations to lower sodium intake, they include in that all the people who are sweating like crazy in an effort to follow guidelines for ever increasing amounts of cardio exercise, along with drinking as much water as they can chug down. No, those people don’t need any salt at all!)

I just ask one thing–please someone please, tell me that they got the title of these posts. “NaCl” rhymes with “debacle”? Kinda sorta?

My family was ready to throttle me over that one.

But you are right about your final note: This was a huge credibility test for me when I would do patient education during my dietetics internship. If I told someone who worked outside (in NC in the summer) to arbitrarily lower sodium (or someone on a diuretic, or any number of other people who knew better), they would tune out everything else I said. So when you look at some of the data, it makes you kinda glad that people don’t seem to really listen to dietitians, right? Might have saved a few lives.

Despite finding “no strong evidence that salt reduction reduced all-cause mortality in normotensives . . . or hypertensives”, and also that one “RCT showed increase the risk of all-cause death in one study in those with congestive heart failure receiving a low salt diet”, the authors conclude that “Our findings are consistent with the belief that salt reduction is beneficial in normotensive and hypertensive people”. Go figure!

This is a definitive review of 48 RCTs of dietary fat with a minimum dietary intervention time of 6 months and with over 65 thousand participants, the conclusion was that dietary fat, whether lowering it or changing the type of fat (i.e from saturated to mono or poly), does not have an effect on mortality, cardiovascular mortality, heart attacks, stroke, cancer, or diabetes. There was a reduction in cardiovascular events associated with changes in dietary fat, but this relationship disappeared when studies with systematic differences in care or with dietary differences other than fat were removed.

And yet: “The findings are suggestive of a small but potentially important reduction in cardiovascular risk on modification of dietary fat, but not reduction of total fat, in longer trials. Lifestyle advice to all those at risk of cardiovascular disease and to lower risk population groups, should continue to include permanent reduction of dietary saturated fat and partial replacement by unsaturates.”

Yeah, go figure. I guess contradicting a Consistent Public Health Message is a scary thing. I’m glad the IOM had the huevos to do it.

Sheesh. Stuff like this makes me wish the “authorities” (be they in government or academia) would make a commercial, and it would go something like this:

One of them could be standing up, holding a basketball, arms extended in front of them. He/she then very deliberately drops the ball and says, “Oops.” Caption running underneath: “You’re on your own, folks!”

Alternative version:

Similar authorities gather on a beach and proceed to lodge their heads as deeply as possible into the sand.

“Similar authorities gather on a beach and proceed to lodge their heads as deeply as possible into the sand.”

I think we just need one nutrition authority to lodge her head in the sand and then the next nutrition authority can lodge her head in the body part of the preceding nutrition authority that most readily presents itself, and so on down the line. I think that visual would most accurate illustrate the current situation.

If I didn’t crack myself up so much, I’d be locked in permanent facepalm.

If your diet NEEDS to include lots of very highly salted foods, it is likely (at least in a traditionally fed society, for example Japanese, Korean or Kosher Jewish), that this is because FRESH foods are not so available. The whole dietary intake pattern related to potassium, magnesium, antioxidants, salicylates, nitrates and anything else that might influence blood pressure and platelet stickiness might be quite different in the highest sodium ranges where this is the case.

Excellent point & this is pretty much what the research shows. There’s something really goofy about pulling out one single electrolyte–albeit a very important one–and ignoring the rest of system. But that’s what you get when you have your head wedged up a Consistent Public Health Message.

I find it rather ironic that the “experts” are even questioning the health effects of salt since it is one of the main ingredients in processed food. Maybe you are right that the use of artificial salt substitutes will be all the rage. Scare the people away from natural salt into the new salt/sodium-free promises of “new and improved healthier” products. In the end, it boils down to a new way to scam consumers into buying new/rerformulated processed foods.

Salt has always been an ingredient in “processed” food–I think for a long time salting (as a part of drying/dehydration) was how you “processed” protein foods in order to preserve them for anything beyond immediate use. The AHA/USDA/HHS has this sort of Grumpy of the 7 dwarves approach to any food that smacks of normal, traditional approaches to eating: “whatever it is, we’re against it.”

Removing salt would mean more processing, hopefully with some ingredient that we can manufacture from corn or soy and that can also be used in say, smartphones and insect repellent.

A little OT, but speaking of being delusional, I just saw a documentary called The Imposter where a 23-year-old, black-haired, brown-eyed Frenchman convinced a family he was their long-lost, blond, blue-eyed 16-year-old son. It was back in the 1990s when people (experts!) still believed in things like recovered memories and satanic baby-eating cults.

Of course I think we should question the motives of anyone who continues to promote dietary recommendations that clearly are, ahem, NOT WORKING. I don’t care if you think they are not working because we don’t follow them, or they are not working because we do, but good grief. They. Are. Not. Working. So can we stop already?